[patch #10479] Bug #66044: Apply address mask in instruction decoder for LD/ST

[Igor Proskurin]

URL:
  <https://savannah.nongnu.org/patch/?10479>

                 Summary: Bug #66044: Apply address mask in instruction
decoder for LD/ST 
                   Group: Simulavr: an AVR simulator
               Submitter: sciprosk
               Submitted: Mon 30 Sep 2024 06:08:46 PM UTC
                Category: bug fix
                Priority: 5 - Normal
                  Status: None
                 Privacy: Public
             Assigned to: None
        Originator Email: 
             Open/Closed: Open
         Discussion Lock: Any
       Component Version: simulavr


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Follow-up Comments:


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Date: Mon 30 Sep 2024 06:08:46 PM UTC By: Igor Proskurin <sciprosk>
Applies `core->dataAddressMask` in LD/ST instructions before writing to
memory. Also, skips updating XH, YH, ZH if `core->dataAddressMask` is less or
equal to 0xFF.

To comply with the clause from the "AVR Instruction Set Manual":
> only the low byte of the X-pointer is updated in devices with no more than
256 bytes of data space. For such devices, the high byte of the pointer is not
used by this instruction and can be used for other purposes.

See also an issue in AVR-LibC: https://github.com/avrdudes/avr-libc/issues/954






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File Attachments:


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Name: apply_address_mask.patch  Size: 7KiB
<https://file.savannah.nongnu.org/file/apply_address_mask.patch?file_id=56467>

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